1. Field of the Invention
The present invention relates to an image reading apparatus that conveys a sheet-like medium and picks up an image of the medium being conveyed.
2. Description of the Related Art
Conventionally, there is an image reading apparatus that conveys a sheet-like medium and picks up an image of the medium being conveyed. In this image reading apparatus, once a sheet-like medium is inserted into an apparatus main unit, it is conveyed to an image pickup device by a conveyor roller, its image is picked up by the image pickup device, and ejected from the apparatus main unit by the conveyor roller.
As a technique related to conveyance of a sheet-like medium, there are inventions in which a sheet-like medium ejected from an apparatus main unit is held by a conveyor roller. This type of invention includes an image pickup device disclosed in Japanese Patent Application Laid-open No. S64-43434 and an image forming apparatus disclosed in Japanese Patent Application Laid-open No. S64-64961, for example.
In the image pickup device disclosed in Japanese Patent Application Laid-open No. S64-43434, a noncompliant sheet, which is determined to have a noncompliant size for re-feeding to an imaging unit including a photoconductor drum or the like by a control circuit, is ejected to outside of an apparatus from a vertical conveyor unit incorporated in a copier main unit by a conveyor roller. A conveyor roller pair near an ejection opening holds the noncompliant sheet ejected outside of the apparatus. That is, in the image pickup device in Japanese Patent Application Laid-open No. S64-43434, the noncompliant sheet is held by the conveyor roller pair near the ejection opening without having the sheet dropped outside of the apparatus, and an operator pulls the noncompliant sheet out from the conveyor roller pair near the ejection opening.
In the image forming apparatus disclosed in Japanese Patent Application Laid-open No. S64-64961, a drive motor is halted by a control unit, and a sheet ejected outside of a machine incorporating a copying unit or the like is sandwiched by an ejection roller pair. That is, in the image forming apparatus disclosed in Japanese Patent Application Laid-open No. S64-64961, the sheet ejected outside of the machine is held by the ejection roller pair without dropping it, and an operator pulls the sheet out from the ejection roller pair.
Among image reading apparatuses, there is a type of apparatus capable of capturing an image of a sheet-like medium while conveying the medium in a stationary state where the apparatus main unit is stationary, or in a non-stationary state where the main unit is not stationary.
For example, Japanese Patent Application Laid-open Nos. H5-35354, H5-35355, H5-134904, and 2008-90345 disclose techniques related to detection of a state of an apparatus main unit. Japanese Patent Application Laid-open Nos. H5-35354 and H5-35355 disclose a technique of detecting, by an inclination detector, an installation inclination change of a portable computer main unit when a state thereof has been shifted from a normal installation state to a held state (hereinafter, the portable computer main unit when the state thereof has been shifted from a normal installation state to a held state is simply referred to as “portable computer at the time of state shifting”), a technique of detecting an installation pressure change of the portable computer main unit at the time of state shifting by a pressure detector, and a technique of detecting a change in an installation distance of the portable computer main unit at the time of state shifting by using an ultrasonic signal or the like. Further, Japanese Patent Application Laid-open No. H5-134904 discloses a technique of recognizing (determining) whether a portable terminal device is in a still state or in a moving state by using an angular moment of inertia. Furthermore, Japanese Patent Application Laid-open No. 2008-90345 discloses a technique of determining whether a usage state of a portable computer is in an installation mode or in a portable mode, according to an output of an acceleration sensor or a signal of a mode detection switch.
In a non-stationary state of an apparatus main unit, when a user tries to pick up an image of a sheet-like medium by an image reading apparatus while holding the apparatus main unit with one hand, the user needs to insert the sheet-like medium with the other free hand and receive the imaged sheet-like medium by the other hand, which is used to insert the sheet-like medium into the apparatus main unit. In the non-stationary state of the apparatus main unit while holding the apparatus main unit with one hand, when the user inserts the sheet-like medium with the other free hand and cannot receive the imaged sheet-like medium by the other hand, the sheet-like medium ejected from the apparatus main unit drops and is damaged. That is, in the non-stationary state of the apparatus main unit, when a conveyor roller is controlled in the same manner as in the conveyor roller in a stationary state of the apparatus main unit, the usability of the image reading apparatus is degraded.